Description Of A New Enantiornithine(PMOL-AB00024) From Lower Cretaceous In Western Liaoning,China

It is described the research hitory,geological background and ecological types of Enantiornithine.collated and summarize the list of officially reported Enantiornithes to date in China,there are 53 species officially reported from the China so far.This paper mainly studies an Enantiornithine from Lower Cretaceous Jiufotang formation in Chaoyang city,Liaoning province,China.through its biological characteristics and phylogenetic taxonomy.According to the traditional method description of bone structure,systematically described the bone of the Enantiornithe fossil in detail,The fossil were identified as small Enantiornithes according to theirsynapomorphies.At the same time,according to the characteristics of it's skull and hind limbs,it can be judged to be a small arboreal Enantiornithine.In this paper,compared and discussed in detail the the new Enantiornithe fossil with other reported small Enantiornithe in bone structure,and some characteristics of the new fossil were found: the skull is high,and short premaxilla,the maxila and mandibular are developed,and the teeth of maxila and mandibular are irregular;The forelimb,pectoral girdle and sternum are relatively developed,but the development of hind limb is somewhat delayed.Therefore,the new fossil have the progressive characteristics and primitive characteristics of Enantiornithes.This paper further confirms the taxonomic position of new fossil in the evolution of birds through phylogenetic taxonomy analysis and comparison of key characteristics.In addition,this paper summarized and analyzed the flight ability and ecological types of new fossil.Based on the above,determined the new fossil to be a small arboreal Enantiornithes with flight ability and feed on insects.